[An outsider views a scientist] as a type of unscrupulous opportunist: he appears as a realist, insofar as he seeks to describe the world independent of the act of perception; as idealist insofar as he looks upon the concepts and theories as the free inventions of the human spirit (not logically derivable from that which is empirically given); as positivist insofar as he considers his concepts and theories justified only to the extent to which they furnish a logical representation of relations among sense experiences. He may even appear as Platonist or Pythagorean insofar as he considers the viewpoint of logical simplicity as an indispensable and effective tool of his research.

[Shawn Lawrence Otto describes the damaging] strategy used to undermine science in the interest of those industries where science has pointed out the dangers of their products to individuals and human life in general [It was] used a generation ago by the tobacco industry First they manufacture uncertainty by raising doubts about even the most indisputable scientific evidence. Then they launder information by using seemingly independent front organizations to promote their desired message and thereby confuse the public. And finally they recruit unscrupulous scientific spokespeople to misrepresent peer-reviewed scientific findings and cherry-pick facts in an attempt to persuade the media and the public that there is still serious debate among scientists on the issue at hand.

In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
(1987) -- Carl Sagan